This section provides background information related to the present disclosure which is not necessarily prior art.
As photographic equipment becomes increasingly popular, exposure control gradually becomes a function attracting more attention of users of the photographic equipment. Besides pursuing a special exposure effect, users generally require reasonably exposing images to obtain richer picture information and avoid information loss, so the automatic exposure function is very necessary for common users. The premise of exposure control is to test light of a current scenario and then carry out image taking.